1. Field of the Invention
The present invention relates to a network for interactive distribution of video, audio and telematic information.
2. Discussion of the Related Art
The cable-distribution of video signals to a group of subscribers localized in a confined area, for example a building, may be performed from a distribution center from which cables go out to each subscriber, and are intended to carry a programme chosen from a group which the distribution center makes available. The subscriber selects a programme by virtue of a means of access to a switching device, commonly referred to as the "switching grid" and situated in the distribution center. This switching device enables a connection to be established between the individual cable of the subscriber and the source of the programme chosen. In order to send control signals to the switching device, this means of access may use the cable serving to transmit the programmes to the subscriber. A known network of this type enables connections to be established between M sources of information to be distributed and a group of N users wishing to receive on request one of the programmes from the sources arriving at the distribution center. The advantage of such a network, which has to transmit one programme only at a time, is to enable the use of low-cost cables which are easy to lay and which are given the job of transmitting over a moderate distance a signal whose frequency standard stays within a restricted pass band. The management of the individual connections of this network with star cabling may be ensured with the aid of logic means of control using a microprocessor.
It is known to sequentially process the selection requests formulated by the subscribers of the network by sending them over a bus intended for this use where these requests are associated with the address of the requester. These requests are processed one after the other which enables verification of the legality of the requests and organization of the pricing.
The disadvantage of microprocessor management of the selection requests is to introduce, a delay into the satisfaction of the requests and to multiplication means which could be common to a large number of users. A lack of flexibility in adapting to more or less important needs, delicate to solve connection problems, and a more difficult to ensure reliability result therefrom.